Displaying similar documents to “Ultrafilter-limit points in metric dynamical systems”

Indiscernibles and dimensional compactness

C. Ward Henson, Pavol Zlatoš (1996)

Commentationes Mathematicae Universitatis Carolinae

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This is a contribution to the theory of topological vector spaces within the framework of the alternative set theory. Using indiscernibles we will show that every infinite set u S G in a biequivalence vector space W , M , G , such that x - y M for distinct x , y u , contains an infinite independent subset. Consequently, a class X G is dimensionally compact iff the π -equivalence M is compact on X . This solves a problem from the paper [NPZ 1992] by J. Náter, P. Pulmann and the second author.

p -sequential like properties in function spaces

Salvador García-Ferreira, Angel Tamariz-Mascarúa (1994)

Commentationes Mathematicae Universitatis Carolinae

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We introduce the properties of a space to be strictly WFU ( M ) or strictly SFU ( M ) , where M ω * , and we analyze them and other generalizations of p -sequentiality ( p ω * ) in Function Spaces, such as Kombarov’s weakly and strongly M -sequentiality, and Kocinac’s WFU ( M ) and SFU ( M ) -properties. We characterize these in C π ( X ) in terms of cover-properties in X ; and we prove that weak M -sequentiality is equivalent to WFU ( L ( M ) ) -property, where L ( M ) = { λ p : λ < ω 1 and p M } , in the class of spaces which are p -compact for every p M ω * ; and that C π ( X ) is a WFU ( L ( M ) ) -space iff...

Finite canonization

Saharon Shelah (1996)

Commentationes Mathematicae Universitatis Carolinae

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The canonization theorem says that for given m , n for some m * (the first one is called E R ( n ; m ) ) we have for every function f with domain [ 1 , , m * ] n , for some A [ 1 , , m * ] m , the question of when the equality f ( i 1 , , i n ) = f ( j 1 , , j n ) (where i 1 < < i n and j 1 < j n are from A ) holds has the simplest answer: for some v { 1 , , n } the equality holds iff v i = j . We improve the bound on E R ( n , m ) so that fixing n the number of exponentiation needed to calculate E R ( n , m ) is best possible.